It's possible, but you're going to be busy as fukk and at times not even going to be able to hit a gym. Especially if the country is at war, and depending on the branch, you may not even have access to a gym for long periods. Let alone the energy to workout. It also depends on your job, as well.

The hardest part about it is the diet and the long hours and constantly changing schedule. Some times you dont have time to lift after work or you have to eat ****ty food because thats all there is, but it is possible with some good planning and motivation.